U.S. Pat. No. 4,773,673 discloses a vehicle occupant restraint apparatus including an inflatable air bag and a source of gas for inflating the air bag. The air bag is stored in a folded condition within a container. The container has a door with a hinge, and is supported in a position in which the door faces a seat in the vehicle occupant compartment.
When the air bag is being inflated by the gas, it expands from its folded condition. The air bag then moves against the inside of the container door and pushes the door outwardly about the hinge. The air bag thus opens the door as the air bag is being expanded by the gas. The air bag continues to expand outwardly past the door and into the vehicle occupant compartment until it reaches a fully inflated condition.
The vehicle occupant restraint apparatus disclosed in the '673 patent further includes a latching unit which secures the door in a closed position until the air bag is to be inflated. The latching unit includes a pivotal latching lever which is supported on the inside of the door. The latching lever has an engaged position in which it engages the adjoining edge of the container to block movement of the door out of the closed position. The latching unit further includes a pressure cylinder which communicates with the source of gas. The pressure cylinder has a piston rod which moves in response to gas pressure in the pressure cylinder. When the air bag is to be inflated, a quantity of the gas is directed from the source to the pressure cylinder. The piston rod then moves in response to the increased gas pressure in the pressure cylinder, and moves against the latching lever to move the latching lever pivotally out of the engaged position. The latching unit thus releases the door for movement out of the closed position when the air bag is to be inflated.
U.S. Pat. No. 4,893,833 also discloses a vehicle occupant restraint apparatus including an inflatable air bag and a source of gas for inflating the air bag. The restraint apparatus disclosed in the '833 patent also has a door which is moved pivotally from a closed position to an open position by the air bag as the air bag expands toward its fully inflated condition. When the door is in the closed position, a frangible tab portion of the door extends into a recess in the vehicle instrument panel. The tab portion of the door and the recess in the instrumental panel establish a mechanical interlock which secures the door in the closed position. When the gas begins to inflate the air bag, the air bag expands and moves forcefully against the inside of the door. The energy of the expanding air bag that is directed against the door causes the tab portion of the door to be sheared away from the door. The restraint apparatus thus releases the door for movement out of the closed position by directing the energy of the expanding air bag against the door to break the tab portion of the door.